Dynamics of coupled light waves and electron-acoustic waves

Electron acoustic shock waves in a collisional plasma

A nonlinear analysis for the finite amplitude electron acoustic wave (EAW) is considered in a collisional plasma. The fluid model is used to describe the two-temperature electron species in a fixed ion background. In general, in electron-ion plasma, the presence of wave nonlinearity, dispersion, and dissipation (arising from fluid viscosity) give rise to the Korteweg-de Vries Burgers (KdVB) equation which exhibits shock wave. In this work, it is shown that the dissipation due to the collision between electron and ion in the presence of collective phenomena (plasma current) can also introduce an anomalous dissipation that causes the Burgers term and thus leads to the generation of electron acoustic shock wave. Both analytical and numerical analysis show the formation of transient shock wave. Relevance of the results are discussed in the context of space plasma.

Localization of intense electromagnetic waves in plasmas

We present theoretical and numerical studies of the interaction between relativistically intense laser light and a two-temperature plasma consisting of one relativistically hot and one cold component of electrons. Such plasmas are frequently encountered in intense laser-plasma experiments where collisionless heating via Raman instabilities leads to a high-energetic tail in the electron distribution function. The electromagnetic waves (EMWs) are governed by the Maxwell equations, and the plasma is governed by the relativistic Vlasov and hydrodynamic equations. Owing to the interaction between the laser light and the plasma, we can have trapping of electrons in the intense wakefield of the laser pulse and the formation of relativistic electron holes (REHs) in which laser light is trapped. Such electron holes are characterized by a non-Maxwellian distribution of electrons where we have trapped and free electron populations. We present a model for the interaction between laser light and REHs, and computer simulations that show the stability and dynamics of the coupled electron hole and EMW envelopes.

Instability and dynamics of two nonlinearly coupled laser beams in a two-temperature electron plasma

We consider nonlinear interactions between two colliding laser beams in an electron plasma, accounting for the relativistic electron mass increase in the laser fields and radiation pressure driven electron-acoustic (EA) perturbations that are supported by hot and cold electrons. By using the hydrodynamic and Maxwell equations, we obtain the relevant equations for nonlinearly coupled laser beams and EA perturbations. The coupled equations are then Fourier analyzed to obtain a nonlinear dispersion relation. The latter is numerically solved to show the existence of new classes of the parametric instabilities in the presence of two colliding laser beams in a two-electron plasma. The dynamics of nonlinearly coupled laser beams in our electron plasma is also investigated. The results should be useful in understanding the nonlinear propagation characteristics of multiple electromagnetic beams in laser-produced plasmas as well as in space plasmas.